The present invention relates to measurement devices in general and more particularly to a device which utilizes articulated sensors for dimensionally characterizing elongate components.
There are numerous components in industrial and utility installations that require on-site inspection to verify continued serviceability. Such inspections may be required before the component is placed in service or it may be part of a maintenance program to ascertain whether the component can continue to be used. Component inspections frequently include dimensional measurements. A notable example, for present purposes, is the on-site inspection of components of a nuclear reactor, especially replaceable components such as control rods, fuel elements, and fuel channels.
For example, a typical fuel assembly having a removable and reusable flow channel is shown in U.S. Pat. No. 3,689,358. Such channel is an elongate square, tubular member often formed of a Zircaloy alloy. It is necessary to assure that the four major exterior surfaces of such channels are sufficiently flat so as to not interfere with the insertion of control rods between fuel assemblies during operation in the nuclear reactor core. Dimensions of interest include face bulge, channel width, non-squareness, longitudinal bow, and twist. Dimensional tolerances over the length of such channel may be on the order of about 0.127 mm.
Since channels and other reactor components which have been in service are radioactive, it is necessary that the measuring device be remotely operable under water to protect the equipment operator from exposure to radiation. Also, it is desirable that the measuring device be sufficiently portable for its repositioning within a water pool, for movement from one pool to another, and for removal to dry storage when not in use. Examples of prior art measuring devices can be found in U.S. Pat. Nos. 4,197,652 and 4,274,205.